1. Field of the Invention
The invention relates generally to interactive television systems and more particularly to a system and method for creating and controlling interactive television content.
2. Description of Related Art
Interactive television systems provide a means to deliver interactive content as well as ordinary television audio and video to a large number of subscribers. Programs broadcast by these systems may incorporate television audio and video, still images, text, interactive graphics and applications, and many other components. They may also provide a number of services, such as commerce via the television, electronic program guides (EPGs), video-on-demand, and other interactive applications to viewers. The interactive content of the interactive television signal may therefore include application code, data associated with the audio and video, control signals, raw data and many other types of information. This information can be combined into a single signal or several signals for transmission to a receiver connected to the viewer's television or the provider can include only a subset of the information.
The interactive functionality of the television is generally controlled by an integrated receiver/decoder (IRD) or similar mechanism, frequently incorporated into a set-top box, connected to the television. The IRD receives the signal provided by a broadcast service provider or system operator and separates the interactive portion from the audio-video portion. The IRD uses the interactive information to, for example, execute an application while the audio-video information is transmitted to the television. The IRD may combine the audio-video information with interactive graphics or audio generated by the interactive application prior to transmitting the information to the television.
Interactive content such as application code or information relating to television programs may be broadcast in a cyclical or repeating format. The pieces of information which are broadcast in this manner form what may be referred to as a “carousel.” A carousel may include multiple modules of data, including a directory module which indicates the particular modules which correspond to a given application. Frequently, a single carousel is transported as a contiguous data stream. However, it is also possible to multiplex two or more carousels in a single data stream. As an alternative to using a carousel format, some systems may utilize a return path to request and/or receive interactive content.
Broadcast systems may transmit information in a carousel format in order to allow receivers in the system to selectively obtain particular pieces of information in the carousel without requiring a return path from the receivers to the server. If a particular receiver needs a particular piece of information, it can simply wait until the next time that piece of information is broadcast, and then extract the information from the broadcast data stream. By employing carousels to broadcast information, the system may eliminate the need to connect each of the receivers with a server and further eliminate the need for the server to process individual requests for information.
The pieces of information, or data objects, in a carousel may be intended to be combined in a single object data stream to form a program. This program may also contain streaming data such as audio or video. For example, an interactive television game show may combine television audio and video with interactive content such as application code which allows users to answer questions. Another example would be a news program which combines audio and video with application code that inserts current stock prices in a banner at the bottom of the screen. Typically, each program is associated with a corresponding channel and, when a channel containing a particular program is selected by the interactive television receiver, the data which is being broadcast on that channel is downloaded and the program is started.
As television receivers become more sophisticated, and include the ability to access a wider range of data and resources, efforts have been made to develop mechanisms to handle these additional resources. For example, the DVB MHP 1.1 specification and DAVIC 1.4.1 Part 9 specification define a URL scheme to access broadcast services. Since DAVIC broadcast networks carry Service Information (SI) that contains globally unique parameters for locating the services in a broadcast network, their URL scheme is able to address services in a physical network independent manner.
Unfortunately, such schemes may not work on ATSC networks or other networks that define different or even proprietary signaling formats. Therefore, a new more flexible scheme is desired.